As an apparatus that dries wet hands after washing, there are hand drying apparatus that blow away water on hands to dry the hands using fast airflow. The hand drying apparatus have a box formed with a hand insertion portion in a recessed shape as a hand drying space, and air nozzles are arranged on the hand insertion portion. The air nozzles are connected with an air duct, connected to a high pressure airflow generator, thereby discharging fast airflow in the hand insertion portion. Water is blown away in the hand drying space by the hand drying, and the water drops from a water drain port provided on a bottom of the hand insertion portion to a drain container provided below the hand insertion portion to be received in the container.
The hand drying apparatus are often constituted such that a hand detector constituted of an infrared light emitter and an infrared light receiver is provided on a wall face that forms the hand drying space. When insertion of hands into the hand drying space is detected by the hand detector, fast airflow is discharged based on a detection signal from the hand detector.
As an arrangement system for the infrared light emitter and the infrared light receiver, there is a detection system of a transmission type where the infrared light emitter and the infrared light receiver are respectively arranged on, for example, a front side wall face and a rear side wall face forming the hand drying space so as to be opposed to each other, and presence of hands is detected based on whether light to the receiver is interrupted. In the detecting system of the transmission type, however, since the infrared light emitter and the infrared light receiver are arranged at different positions, the structure of a main unit of the detecting system is complicated, which causes such a problem as increase in pressure loss in an air duct, or increase in cost of the main unit.
Patent document 1 discloses a hand detector of a reflected light detection type where an infrared light emitter and an infrared light receiver that detect hands inserted into a hand drying space are arranged on the same wall face. In the Patent document 1, such a constitution is employed that the infrared light emitter and the infrared light receiver provided on the same wall face are obliquely aimed on a position below and inside an air outlet, so that a hand detecting range is limited and improper operations are prevented even if a person other than a user of the hand drying apparatus approaches to its main unit.    Patent Document 1: Japanese Patent Application Laid-open No. H11-318760